Method of manufacturing thin film magnetic head

ABSTRACT

A method of manufacturing a thin-film magnetic head allowing dimension control of the width of the magnetic pole and reduction of the time required for formation is provided. A layer of iron nitride formed by sputtering is selectively etched with the RIE to form a top pole tip. In this etching process with RIE, chlorine-type gas is selected as a gas seed for etching, and the process temperature is in a range of 50° C. to 300° C. Subsequently, using part of a first mask and a tip portion of the top pole tip as a mask, part of both the write gap layer and the second bottom pole are etched with the RIE similarly to the above process, to thereby form a magnetic pole. The etching conditions are optimized by performing the process with the RIE under the above conditions, so that both of the top pole tip and the magnetic pole can be formed with high precision, and that the time required for forming both of these elements can be significantly reduced.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method of manufacturing athin-film magnetic head having at least an inductive-type magnetictransducer for writing.

[0003] 2. Description of the Related Art

[0004] Improvements in the performance of a thin-film magnetic head havebeen sought since a surface recording density of a hard disk drive hasbeen improved. A composite thin-film magnetic head having a structure inwhich, a recording head having an inductive-type magnetic transducer forwriting and a reproducing head having a magnetoresistive (hereinafterreferred to as MR) element for reading are stacked, is widely used asthe thin-film magnetic head. The MR element includes an AMR elementusing an anisotropic magnetoresistive (hereinafter referred to as AMR)effect and a GMR element using a giant magneto resistive (hereinafterreferred to as GMR) effect. The reproducing head using the AMR elementis called an AMR head or simply an MR head, and the reproducing headusing the GMR element is called a GMR head. The AMR head is used as areproducing head whose surface recording density is over 1 gigabit persquare inch, and the GMR head is used as the reproducing head whosesurface recording density is over 3 gigabit per square inch.

[0005] The AMR head comprises an AMR film having the AMR effect. The GMRhead has a structure identical to the AMR head except that a GMR filmhaving the GMR effect is used in place of the AMR film. However, whenthe same external magnetic field is applied, the GMR film exhibitsgreater change in resistance than the AMR film. As a result, the GMRhead can increase the reproduction output in the order of three to fivetimes the AMR head.

[0006] In order to improve the performance of the reproducing head, amethod of replacing the AMR film with a material having bettermagnetoresistive sensitivity such as the GMR film as the MR film, amethod of making an appropriate pattern width of the MR film, especiallythe MR height and other methods are employed. The MR height is adistance between an end of the MR element on the air bearing surfaceside to an end thereof on the other side, and it is controlled by apolishing amount in processing the air bearing surface. The air bearingsurface, here, is a surface of the thin film magnetic head facing amagnetic recording medium, and is called a track surface as well.

[0007] On the other hand, improvements in performance of a recordinghead have been desired while performance in a reproducing head hasimproved. A factor which determines the performance of the recordinghead is a throat height. The throat height is a length of a pole betweenthe air bearing surface and an edge of an insulating layer whichelectrically separates a thin-film coil for generating magnetic flux.The throat height is desired to be optimized in order to improve theperformance of the recording head. The throat height is controlled by apolishing amount in processing the air bearing surface.

[0008] To improve a recording density among the performance of therecording head, a track density of the magnetic recording medium needsto be increased. In order to achieve such an increase, a recording headwith a narrow track structure needs to be realized in which a width ofthe top and bottom poles on the air bearing surface, which are formed ontop and bottom sandwiching a write gap, is reduced from the order ofsome microns to sub-microns. Semiconductor process techniques areemployed to achieve the narrow track structure.

[0009] A method of manufacturing the composite thin-film magnetic headas an example of the methods of manufacturing the thin-film magnetichead of the related art will be described by referring to FIG. 27through FIG. 32.

[0010] As shown in FIG. 27, in this manufacturing method, an insulatinglayer 102 made of, for example, aluminum oxide (Al₂O₃; hereinafterreferred to simply as “alumina”) of about 5 μm to 10 μm in thickness isdeposited on a substrate 101 made of, for example, altic (aluminum oxideand titanium carbide; Al₂O₃.TiC). A bottom shield layer 103 for areproducing head is formed on the insulating layer 102. A shield gapfilm 104 is formed on the bottom shield layer 103 by, for example,sputter-depositing alumina with 100 nm to 200 nm in thickness. An MRfilm 105 of tens of nanometers in thickness for making up the MR elementfor reproduction is formed on the shield gap film 104, and patterned ina desired shape through photolithography with high precision. Next,after forming lead layers (not shown) on both sides of the MR film 105as an extraction electrode layer which is electrically connected to theMR film 105, a shield gap film 106 is formed on the lead layer, theshield gap film 104 and the MR film 105, and then the MR film 105 isburied in the shield gap films 104 and 106. Further, a topshield-cum-bottom pole (hereinafter referred to simply as a bottom pole)107 made of magnetic materials, such as ferronickel (NiFe; hereinafterreferred to simply as “permalloy” (trade name)) used for bothreproduction and recording heads is formed on the shield gap film 106.

[0011] As shown in FIG. 28, a write gap layer 108 made of an insulatingmaterial, such as alumina, is formed on the bottom pole 107, and aphotoresist film 109 in a desired pattern is formed on the write gaplayer 108 through photolithography with high precision. Next, athin-film coil 110 for an inductive-type recording head made of, forexample, copper (Cu) is formed on the photoresist film 109 by, forexample, plating. A photoresist film 111 in a desired pattern is formedcovering the photoresist film 109 and the thin-film coil 110 throughphotolithography with high precision. Next, the photoresist film 111 issubjected to a heat treatment at a temperature of, for example, 250° C.to have turns of the coil 110 insulated from each other.

[0012] As shown in FIG. 29, an opening 108 a is formed by partiallyetching the write gap layer 108 in a position behind the coil 110(right-hand side in FIG. 29) to expose part of the bottom pole 107 inorder to form a magnetic path. A film of a magnetic material with a highsaturation magnetic flux density, such as permalloy, is formed by anelectrolytic plating, covering the exposed surface of the bottom pole107, and the photoresist film 111 and the write gap layer 108. Theplated film formed of permalloy is selectively etched by ion millingusing a mask (not shown) formed of a photoresist film having aprescribed planar shape, to thereby form a top yoke-cum-top pole(hereinafter referred to as a top pole) 112. The top pole 112 has, forexample, such a planar shape as shown in FIG. 32, which will bedescribed hereinafter, and includes a yoke 112 a and a pole tip 112 b.The top pole 112 has a contact with the bottom pole 107 in the opening108 a being magnetically coupled. Next, after both the write gap layer108 and the bottom pole 107 are partially etched about 0.5 μm by ionmilling using part of the top pole 112 (the pole tip 112 b) as a mask(see FIG. 31), an overcoat layer 113 is formed of a material, such asalumina, on the top pole 112. The thin-film magnetic head is completedafter a track surface, that is, air bearing surface 120 of the recordinghead and reproducing head is formed by machining or polishing.

[0013]FIG. 30 through FIG. 32 show a completed configuration of thethin-film magnetic head. FIG. 30 shows a cross-sectional view of thethin-film magnetic head orthogonal to the air bearing surface 120, FIG.31 is an enlarged cross-sectional view of the pole in parallel to theair bearing surface 120, and FIG. 32 is a plan view. FIG. 29 is a crosssectional view taken along the line XXIX-XXIX in FIG. 32. Illustrationsof the overcoat layer 113 and the like are omitted in FIG. 30 to FIG.32. The thin-film coil 110 shown in FIG. 32 is only the outermostperiphery portion thereof, and the photoresist film 111 shown therein isonly the outermost end thereof.

[0014] In FIG. 30 and FIG. 32, “TH” stands for throat height, and “MR-H”stands for MR height. In both of these figures, “TH0 position” is theposition of the end of the photoresist layer 111, which serves as aninsulating layer for electrically insulating the thin-film coil 110,located nearest to the air bearing surface 120. This is the referenceposition in defining a throat height, that is, a throat height zeroposition. Meanwhile, “MRH0 position” is the position of the end of theMR film 105 which is farthest from the air bearing surface 120, i.e. anMR height zero position.

[0015] Other than the throat height (TH) and the MR height (MR-H), oneof the factors that determine the performance of the thin-film magnetichead is an apex angle (θ) shown in FIG. 30. The apex angle θ is theaverage tilt angle of the slope of the photoresist film 111 located onthe side closer to the air bearing surface 120.

[0016] As shown in FIG. 31, a structure in which the write gap layer 108and the bottom pole 107 are both partially etched in a self-alignedmanner to the pole tip 112 b of the top pole 112 is called a trimstructure. The trim structure prevents an increase in the effectivetrack width, which would otherwise be occurred through expansion of themagnetic flux generated during writing of a narrow track. In FIG. 31,“P2W” represents a width of the portion with the trim structure(hereinafter referred to simply as a “pole tip 200”), that is, a polewidth or a “track width”. In the same figure, “P2L” represents thethickness of the pole tip 112 b forming part of the pole tip 200, thatis, the length of the pole. As shown in FIG. 31, lead layers 121 as anextraction electrode layer being electrically connected to the MR film105 is provided on both sides of the MR film 105. However, anillustration of the lead layers 121 is omitted in FIG. 27 to FIG. 30.

[0017] As shown in FIG. 32, the top pole 112 is composed mostly of theyoke 112 a. The top pole 112 includes the pole tip 112 b having analmost uniform width as the pole width P2W as well. At a couplingportion of the yoke 112 a and the pole tip 112 b, an outer periphery ofthe yoke 112 a has an angle a against a surface parallel to the airbearing surface 120. At the above coupling portion, an outer peripheryof the pole tip 112 b has an angle β against the surface parallel to theair bearing surface. Here, α is, for example, about 45 degrees, and β is90 degrees. As described above, the pole tip 112 b serves as a mask forforming the trim structure of the pole tip 200. As can be seen from FIG.30, the pole tip 112 b extends over the flat write gap layer 108, whilethe yoke 112 a extends over a coil portion (hereinafter referred to asan “apex portion”) covered with the photoresist film 111 and raised likea hill.

[0018] The characteristics of the structure of the top pole is disclosedin detail in, for example, Unexamined Patent Application Publication No.Hei 8-249614. This publication discloses a top pole with a structurewhere the width of the portion located behind the TH0 position (the sidefarther away from the air bearing surface 120) is gradually widened.

[0019] As the pole width P2W of the pole tip 200 defines the recordingtrack width on a recording medium, it is required that the pole tip 200is formed with high precision and that the pole width P2W is reduced inorder to increase recording density. If the pole width P2W is too greatin value, a phenomenon in which data is written also to the areaadjacent to a predetermined recording track area on the recordingmedium, that is, a side erase phenomenon, occurs, thereby preventingimprovement in recording density. Therefore, it is important tosimultaneously reduce the pole width P2W of the pole tip 200 and havesuch a pole width P2W that is constant throughout the thicknessdirection (vertical direction in FIG. 31) and the length direction(horizontal direction in FIG. 30).

[0020] The top pole 112 can be formed by a wet process, such as a frameplating, or by a dry process in which a plated film formed of, forexample, permalloy is selectively etched and patterned by ion milling,as described above.

[0021] However, the applicants have confirmed that the ion millingbrings about the following problems. For example, when ion beam isirradiated from a direction substantially perpendicular to the surfaceof the plated film (a direction at an angle of 0 degree to 30 degrees tothe perpendicular line to the surface of the plated film), the etchingproduct generated in etching is reattached to the unetched portion,whereby the width of the pole tip 112 is partially increased from thedesigned value. On the other hand, when, for example, ion beamirradiation is performed from a direction substantially parallel to thesurface of the plated film (a direction at an angle of 50 degrees to 70to the perpendicular line to the surface of the plated film), theabove-described reattachment of the etching product can be prevented.However, the etching amount is increased as the process proceeds,leading to partial decrease in width of the pole tip 112 b from thedesigned value. When the pole tip 200 is formed by ion milling under thelatter conditions above in particular, the pole width P2W will beinconstant as shown in FIG. 33.

[0022] In the related art method, since the photoresist pattern obtainedby selectively exposing to light the photoresist film formed on theplated film is used as a mask for patterning the plated film ofpermalloy. This deteriorates precision in forming the mask due toadverse effects of the light reflected from the surface of theunderlying permalloy layer having a high reflectance.

[0023] Further, according to the method of the related art, the pole tip200 is formed by ion milling with a lower etching rate, and thereforeetching process takes a long time, requiring a considerable time tofinish processing of the pole tip 200. Such a tendency is not limited toformation of the pole tip 200, but the same applies to formation of thetop pole 112 and other magnetic layers (such as the bottom shield layer103, the bottom pole 107, and the like).

SUMMARY OF THE INVENTION

[0024] The present invention has been conceived in view of theabove-described problems. It is an object of the invention to provide amethod of manufacturing a thin-film magnetic head that enables formationof the thin-film magnetic head with high precision and in a short time.

[0025] The present invention provides a method of manufacturing athin-film magnetic head which comprises first and second magnetic layerseach including a magnetic pole and magnetically coupled to each other,the magnetic poles facing each other with a gap layer in between andbeing to be faces with a recording medium, and a thin-film coil portiondisposed between the two magnetic layers with an insulating film inbetween. The first magnetic layer includes a first magnetic layerportion having a first uniform width portion that defines a track width,and a second magnetic layer portion extending a region where thethin-film coil portion is disposed and magnetically coupled to the firstmagnetic layer portion. The second magnetic layer includes a seconduniform width portion corresponding to the first uniform width portionof the first magnetic layer. In this method of manufacturing a thin-filmmagnetic head of the invention, at least one of the step of forming thefirst magnetic layer and the step of forming the second magnetic layerincludes the steps of forming a magnetic material layer, and selectivelyetching the magnetic material layer by reactive ion etching.

[0026] According to the method of manufacturing a thin-film magnetichead of the invention, the magnetic material layer is selectively etchedand patterned by reactive ion etching, whereby at least one of the firstand second magnetic layers is formed. Since the speed of etching processis generally faster with the reactive ion etching than the ion milling,at least one of the first and second magnetic layers can be formed in ashort time.

[0027] In the method of manufacturing a thin-film magnetic head of theinvention, a first mask formed of a predetermined inorganic material maybe used in the step of selective etching. In such a case, preferably amaterial for forming the first mask contains aluminum oxide or aluminumnitride.

[0028] Further, in the method of manufacturing a thin-film magnetic headof the invention, the step of forming the first mask may include thesteps of forming a mask precursor layer made of an inorganic material ona surface of a magnetic material layer, forming a second mask on asurface of the mask precursor layer, and forming the first mask bypatterning the mask precursor layer with use of the second mask. In sucha case, the first mask is preferably formed by reactive ion etching.

[0029] Further, in the method of manufacturing a thin-film magnetic headof the invention, a photoresist film pattern having a predeterminedshape may be formed on the surface of the mask precursor layer and usedas the second mask, or a metal film pattern having a predetermined shapemay be formed on the surface of the mask precursor layer and used as thesecond mask. When the metal film pattern is used as the second mask, themetal film pattern may be formed by selectively plating on the surfaceof the mask precursor layer, or the metal film pattern may be formed byforming a metal layer on the surface of the mask precursor layer andselectively etching the metal layer.

[0030] Further, in the method of manufacturing a thin-film magnetic headof the invention, at least the first uniform width portion of the firstmagnetic layer may be formed by the step of selective etching, or, atleast the second uniform width portion of the second magnetic layer maybe formed by the step of selective etching.

[0031] Further, in the method of manufacturing a thin-film magnetic headof the invention, the gap layer excluding a portion corresponding to thefirst uniform width portion of the first magnetic layer may beselectively removed by reactive ion etching. In such a case, formationof the first uniform width portion of the first magnetic layer, theabove selective removal of the gap layer, and formation of the seconduniform width portion of the second magnetic layer are preferablyachieved successively. In addition, in processing the above portions,preferably, the first uniform width portion of the first magnetic layeris formed by using the first mask made of an inorganic material, and theselective removal of the gap layer and the formation of the seconduniform width portion of the second magnetic layer are achieved by usingas a mask at least one of the first mask and the first uniform widthportion.

[0032] Further, in the method of manufacturing a thin-film magnetic headof the invention, in the step of forming the first magnetic layer, thesecond magnetic layer portion may be formed separately from the firstmagnetic layer portion by reactive ion etching.

[0033] Further, in the method of manufacturing a thin-film magnetic headof the invention, when the thin-film magnetic head further includes amagnetic transducer film extending in a direction away from arecording-medium-facing surface to be faced with the recording mediumand a third magnetic layer magnetically shielding the magnetictransducer film, the third magnetic layer may be formed by reactive ionetching.

[0034] Further, in the method of manufacturing a thin-film magnetic headof the invention, the magnetic layer may be formed by sputtering using apredetermined magnetic material. In such a case, preferably, themagnetic material contains iron nitride or an amorphous alloy, such as amaterial containing zirconium-cobalt-iron.

[0035] Further, in the method of manufacturing a thin-film magnetic headof the invention, the step of selective etching is preferably performedin a gas atmosphere containing at least one of chlorine, borondichloride, boron trichloride, and hydrogen chloride, and at atemperature in a range of 50° C. to 300° C.

[0036] The present invention provides a method of manufacturing athin-film magnetic head which includes first and second magnetic layerseach including a magnetic pole and magnetically coupled to each other,the magnetic poles facing each other with a gap layer in between andbeing to be faced with a recording medium, and a thin-film coil portiondisposed between the two magnetic layers with an insulating film inbetween. The first magnetic layer includes a first magnetic layerportion having a first uniform width portion that defines a track width,and a second magnetic layer portion extending a region where thethin-film coil portion is disposed and magnetically coupled to the firstmagnetic layer portion. The second magnetic layer includes a seconduniform width portion corresponding to the first uniform width portionof the first magnetic layer. This method of manufacturing a thin-filmmagnetic head includes a first etching step of selectively etching atleast one of the first magnetic layer, the gap layer, and the secondmagnetic layer by reactive ion etching, and a second etching step ofselectively etching at least one of the first magnetic layer, the gaplayer, and the second magnetic layer by focused ion beam etching. Thesecond etching step is performed after the first etching step, tothereby achieve formation of the first uniform width portion of thefirst magnetic layer, selective removal of the gap layer excluding aportion corresponding to the first uniform width portion, and formationof the second uniform width portion of the second magnetic layer.

[0037] According to the method of manufacturing a thin-film head of theinvention, the first etching process is performed with reactive ionetching, and then the second etching process is performed with focusedion beam etching, so that a magnetic pole tip composed of the firstuniform width portion, a portion of the gap layer corresponding to thefirst uniform width portion and the second uniform width portion isformed. Since etching process with the focused ion beam etching enablesprocessing with higher precision than the etching process with reactiveion etching, the width of the magnetic pole can be reduced with highprecision by forming the magnetic pole through both the first and secondetching processes as compared with the case where only the first etchingprocess is performed.

[0038] Further, in the method of manufacturing a thin-film magnetic headof the invention, in the second etching step, both the gap layer and thesecond magnetic layer may be partially etched to form two grooveportions in the second magnetic layer so that a region sandwiched by thetwo groove portions may serve as the second uniform width portion of thesecond magnetic layer. In such a case, the groove portion is preferablyformed to have a width of at least 1 μm.

[0039] Other and further objects, features and advantages of theinvention will appear more fully from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0040]FIGS. 1A and 1B are cross-sectional views for describing one stepof a method of manufacturing a thin-film magnetic head of a firstembodiment of the present invention.

[0041]FIGS. 2A and 2B are cross-sectional views for describing the stepcontinued from FIGS. 1A and 1B.

[0042]FIGS. 3A and 3B are cross-sectional views for describing the stepcontinued from FIGS. 2A and 2B.

[0043]FIGS. 4A and 4B are cross-sectional views for describing the stepcontinued from FIGS. 3A and 3B.

[0044]FIGS. 5A and 5B are cross-sectional views for describing the stepcontinued from FIGS. 4A and 4B.

[0045]FIG. 6 is a perspective view for describing the step between thesteps shown in FIGS. 1A and 1B and FIGS. 2A and 2B.

[0046]FIG. 7 is a perspective view for describing the step continuedfrom FIG. 6.

[0047]FIG. 8 is a perspective view for describing the step continuedfrom FIG. 7.

[0048]FIG. 9 is a perspective view corresponding to the cross-sectionalviews of FIGS. 2A and 2B.

[0049]FIG. 10 is a perspective view corresponding to the cross-sectionalviews of FIGS. 3A and 3B.

[0050]FIG. 11 is a perspective view corresponding to the cross sectionalviews of FIGS. 5A and 5B.

[0051]FIG. 12 is a plan view illustrating a planar structure of thethin-film magnetic head of the first embodiment of the presentinvention.

[0052]FIGS. 13A and 13B are cross-sectional views illustrating avariation of the top yoke in the thin-film magnetic head of the firstembodiment of the present invention.

[0053]FIG. 14 is a perspective view for describing a variation of themethod of forming the top pole tip of the first embodiment of thepresent invention.

[0054]FIG. 15 is a perspective view for describing the step continuedfrom FIG. 14.

[0055]FIG. 16 is a perspective view for describing another variation ofthe method of forming the top pole tip of the first embodiment of thepresent invention.

[0056]FIG. 17 is a perspective view for describing the step continuedfrom FIG. 16.

[0057]FIG. 18 is an enlarged plan view illustrating the pole and itssurrounding area for describing a variation of the method of forming thepole.

[0058]FIG. 19 is a cross sectional view corresponding to the plan viewof FIG. 18.

[0059]FIG. 20 is a perspective view corresponding to the cross-sectionalview of FIG. 19.

[0060]FIGS. 21A and 21B are cross-sectional views for describing onestep of a method of manufacturing a thin-film magnetic head of a secondembodiment of the present invention.

[0061]FIGS. 22A and 22B are cross-sectional views for describing thestep continued from FIGS. 21A and 21B.

[0062]FIGS. 23A and 23B are cross-sectional views for describing thestep continued from FIGS. 22A and 22B.

[0063]FIGS. 24A and 24B are cross-sectional views for describing thestep continued from FIGS. 23A and 23B.

[0064]FIGS. 25A and 25B are cross-sectional views for describing thestep continued from FIGS. 24A and 24B.

[0065]FIG. 26 is a plan view illustrating a planar structure of thethin-film magnetic head of the second embodiment of the presentinvention.

[0066]FIG. 27 is a cross-sectional view for describing one step of amethod of manufacturing a thin-film magnetic head of a related art.

[0067]FIG. 28 is a cross-sectional view for describing the stepcontinued form FIG. 27.

[0068]FIG. 29 is a cross-sectional view for describing the stepcontinued from FIG. 28.

[0069]FIG. 30 is a cross-sectional view illustrating the structure of animportant part of the thin-film magnetic head of the related art.

[0070]FIG. 31 is a view illustrating a cross section, in parallel to theair bearing surface, of the pole in the thin-film magnetic head shown inFIG. 30.

[0071]FIG. 32 is a plan view illustrating the structure of the thin-filmmagnetic head of the related art.

[0072]FIG. 33 is a view illustrating a cross section of the pole inparallel to the air bearing surface for describing problems in formingthe pole of the thin-film magnetic head of the related art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0073] Preferred embodiments of the invention will now be described indetail with reference to the accompanying drawings.

[0074] First Embodiment

[0075] An exemplary method of manufacturing a composite thin-filmmagnetic head as a method of manufacturing a thin-film magnetic headaccording to a first embodiment of the invention will be described withreference to FIGS. 1A and 1B to FIG. 11. The thin-film magnetic head ofthis embodiment will be described together with the method ofmanufacturing a thin-film magnetic head of this embodiment because it isembodied by this method.

[0076] Each FIGS. 1A to 5A illustrates a cross section perpendicular toan air bearing surface, while each FIGS. 1B to 5B illustrates a crosssection in parallel to the air bearing surface of a pole. FIG. 6 to FIG.11 are perspective views corresponding to major manufacturing process.More specifically, FIG. 9 to FIG. 11 correspond to the states shown inFIG. 2, FIG. 3, and FIG. 5, respectively. It should be noted, however,that an insulating film 12, a thin-film coil 13, and the like in FIG. 3are not shown in FIG. 10, and that insulating films 12 and 14, thethin-film coil 13, an overcoat layer 15, and the like in FIG. 5 are notshown in FIG. 11.

[0077] In the following description, the X-axis, Y-axis, and Z-axisdirections in FIGS. 1A and 1B to FIG. 11 are referred to as “widthdirection”, “height direction”, and “thickness direction”, respectively.In addition, the air bearing surface side (or the side on which the airbearing surface 20 is formed in a later step) in the Y-axis direction isreferred to as “front side (or in front)”, and the opposite side as“rear side (or behind)”.

[0078] Method of Manufacturing a Thin-Film Magnetic Head

[0079] According to the manufacturing method of the present embodiment,as shown in FIGS. 1A and 1B, an insulating layer 2 formed of, forexample, alumina and having a thickness of approximately 3 μm to 5 μm isfirst deposited on a substrate 1 formed of, for example, altic(Al₂O₃.TiC). On the insulating layer 2, a permalloy of approximately 3μm in thickness is selectively formed by photolithography and plating,to thereby form a bottom shield layer 3 for a reproduction head.

[0080] As also shown in FIGS. 1A and 1B, for example, alumina having athickness of approximately 100 nm to 200 nm is sputter-deposited on thebottom shield layer 3, thereby forming a shield gap film 4. An MR film 5for constituting an MR element, which is an important part of thereproduction head, is formed on the shield gap film 4, and patterned toa desired shape through high precision photolithography. Lead layers(not shown) serving as an extraction electrode layer electricallyconnected to the MR film 5 is formed on both sides of the MR film 5.Thereafter, a shield gap film 6 is formed on the lead layers, the shieldgap film 4 and the MR film 5, so that the MR film 5 is buried in theshield gap films 4 and 6. It should be noted that the MR film 5described above corresponds to one specific example of a “magnetictransducing function element film” of the invention.

[0081] As shown in FIGS. 1A and 1B, a top shield-cum-bottom pole(hereinafter referred to simply as a “bottom pole”) 7 is thenselectively formed on the shield gap film 6. This bottom pole 7 isformed to have a two-layered structure as described below. For example,permalloy having a thickness of approximately 1.5 μm to 2.5 μm is formedon the shield gap film 6 by such a method as an electrolytic plating orthe like. On the thus formed permalloy layer, about 1 μm to 2 μm inthickness is formed of a material, such as iron nitride (FeN), by, forexample, sputtering. The above permalloy and iron nitride layers aresuccessively etched and patterned by a reactive ion etching (hereinafterreferred to simply as “RIE”) using a mask with prescribed shape andmaterial, so that a first bottom pole 7 a of permalloy and a secondbottom pole 7 b of iron nitride are selectively formed. The first bottompole 7 a and the second bottom pole 7 b are magnetically coupled bybeing in contact with each other. The above step of patterning theobtained layer of iron nitride by RIE will be described hereinafter indetail. It should be noted that the bottom shield layer 3 and the bottompole 7 (top shield layer) correspond to one specific example of a “thirdmagnetic layer” of the invention, and the bottom pole 7 composed of thefirst and second bottom poles 7 a and 7 b, respectively, corresponds toone specific example of a “second magnetic layer” of the invention.

[0082] Next, as shown in FIGS. 1A and 1B, an insulating film 300 ofalumina is formed over the entire surface of the layer structure asmentioned above, and the surface of the insulating film 300 is polishedby, for example, a chemical mechanical polishing (CMP) until the secondbottom pole 7 b is exposed, whereby the entire surface is planarized.

[0083] As shown in FIGS. 2A and 2B, a write gap layer 8 of, for example,alumina having a thickness of approximately 0.15 μm to 0.3 μm is formedby sputtering or the like on the second bottom pole 7 b. At this time,an opening 8 b is formed in the write gap layer 8, so that the bottompole 7 is brought into contact with a top pole 11 (a top pole tip 11 a,a magnetic path connection portion 11 b, and a top yoke 11 c) which willbe formed in a later step. It should be noted that the write gap layer 8corresponds to one specific example of a “gap layer” of the invention.

[0084] As shown in FIGS. 2A and 2B, on a region of the write gap layer 8located in front of the region where the thin-film coil 13 will bedisposed in a later step, an insulating film pattern 10 of about 0.5 μmto 1.5 μm in thickness is selectively formed of, for example, organicphotoresist through photolithography with high precision. The insulatingfilm pattern 10 is subjected to heat treatment at a temperature of, forexample, 200° C. to 250° C.. As a result of this heat treatment, theinsulating film pattern 10 has a rounded slope in the vicinity of itsedge portion. This insulating film pattern 10 defines the throat heightzero position (TH0 position) which is the reference position fordetermining the throat height (TH), and also defines the apex angle (θ).

[0085] As shown in FIGS. 2A and 2B and FIG. 9, the top pole tip 11 a ofabout 1.5 μm to 2.5 μm in thickness, constituting part of the top pole11, is selectively formed of, for example, iron nitride in a regionextending from the surface of a front portion of the insulating filmpattern 10 to the area located over the flat write gap layer 8 in frontof the insulating film pattern 10. At the same time the top pole tip 11a is formed, the magnetic path connection portion 11 b (not shown inFIG. 9), which is also part of the top pole 11, is formed in the opening8 b. The top pole tip 11 a has such a planar shape as that shown in FIG.12, which will be described hereinafter, and has a tip portion 11 a(1)having a uniform width defining a recording track width on a recordingmedium (not shown), and an widened width portion 11 a(2) having a widthgreater than the tip portion 11 a(1). It should be noted that the toppole tip 11 a corresponds to one specific example of a “first magneticlayer portion” of the invention.

[0086] Reference to FIGS. 2A and 2B and FIG. 9 as well as FIG. 6 to FIG.8, a method of forming the top pole tip 11 a will be described indetail.

[0087] First, as shown in FIG. 6, a magnetic material with highsaturation magnetic flux density, such as iron nitride, is formed tohave a thickness of approximately 1.5 μm to 2.5 μm over the entiresurface of the layer structure as described above by sputtering, tothereby form a top pole tip precursor layer 111 a (hereinafter referredto simply as an “iron nitride layer” as well). This top pole tipprecursor layer 111 a is a preparation layer which is patterned byetching in a later step to serve as a top pole tip 11 a. In thefollowing description, such a preparation layer which will be patternedto a predetermined shape in a later step is called, and represented as,a “precursor layer”. The top pole tip precursor layer 111 a may beformed of other materials than iron nitride, such as an amorphous alloywith a high saturation magnetic flux density, namely,zirconium-cobalt-iron (FeCoZr) and the like. On the top pole tipprecursor layer 111 a, a first mask precursor layer 121 a of about 2 μmto 3 μm in thickness is formed of an inorganic material, such asalumina, by sputtering or the like. The first mask precursor layer 121 awill be patterned by etching in a later step, and serve as a first mask21 a used for patterning the top pole tip precursor layer 111 a. Otherthan alumina, such an inorganic material as aluminum nitride (AlN) mayalso be used for forming the first mask precursor layer 121 a.Photoresist is applied on the first mask precursor layer 121 a to form asecond mask precursor layer 131 a of a photoresist film. The second maskprecursor layer 131 a will be patterned through photolithography in alater step, and serve as a second mask 31 a used for patterning thefirst mask precursor layer 121 a. It should be noted that the top poletip precursor layer 111 a corresponds to one specific example of a“magnetic material layer” of the invention, and the first mask precursorlayer 121 a corresponds to one specific example of a “mask precursorlayer” of the invention.

[0088] The second mask precursor layer 131 a of a photoresist film isselectively exposed to light and patterned through photolithography, tothereby form the second mask 31 a, as shown in FIG. 7. The second mask31 a has a shape corresponding to a planar shape of the top pole tip 11a. By using an inorganic material with a relatively low reflectance,such as alumina, for forming the first mask precursor layer 121 a lyingunder the second mask precursor layer 131 a, almost no reflected lightgenerates from the surface of the first mask precursor layer 121 aduring light exposure in the photolithography step, deformation of thepattern can be suppressed which would otherwise be caused by an increaseor a decrease in exposure area. As a result, especially the very smalluniform width portion of the second mask 31 a that corresponds to thepole can be formed with high precision. The above-described patterningof the second mask precursor layer 131 a need not be achieved byphotolithography, and the second mask precursor layer 131 a may beselectively etched by RIE, ion milling, or the like. It should be notedthat the second mask 31 a corresponds to one specific example of a“second mask” of the invention as a “photoresist film pattern”.

[0089] By selectively etching the first mask precursor layer 121 athrough RIE using the second mask 31 a, the first mask 21 a of aluminais formed, as shown in FIG. 8. Through this etching process, the firstmask precursor layer 121 a (not shown in FIG. 8) is selectively removedto leave the portion that corresponds to the second mask 31 a. Similarlyto the second mask 31 a, the first mask 21 a has a shape correspondingto the planar shape of the top pole tip 11 a. At the same time theregion of the first mask precursor layer 121 a, uncovered with thesecond mask 31 a, is etched, the second mask 31 a itself is etched,resulting in a reduction in thickness of the second mask 31 a. Thesecond mask 31 a need not to remain when formation of the first mask 21a is completed, and be eliminated in the etching process.

[0090] By selectively etching the top pole tip precursor layer 111 athrough RIE using the first mask 21 a, the top pole tip 11 a of ironnitride is formed, as shown in FIGS. 2A and 2B and FIG. 9. Through thisetching process, the top pole tip precursor layer 111 a (not shown inFIGS. 2A and 2B and FIG. 9) is selectively removed to leave the portionthat corresponds to the first mask 21 a. It should be noted that theetching product can be prevented from reattaching to the peripheral wallof the unetched portion (masked portion of the top pole tip 11 a) duringthe etching process with RIE by using iron nitride, an amorphous alloy(zirconium-cobalt-iron), or the like for forming the top pole tipprecursor layer 111 a. Therefore, especially the tip portion 11 a(1) ofthe top pole tip 11 a can be formed with high precision.

[0091] It is preferable in the etching process with RIE that the processtemperature is in a range of 50° C. to 300° C., and that gas containingat least one of chlorine (Cl₂), boron dichloride (BCl₂), borontrichloride (BCl₃), and hydrogen chloride (HCl), with hydrogen (H₂),oxygen (O₂), argon (Ar), and the like added thereto is used as etchinggas. Employing such conditions allows the etching process with RIE to becompleted in a short time. In particular, when the top pole tipprecursor layer 111 a is etched with RIE, the process temperature in arange of 150° C. to 250° C. is preferable as a condition for the aboveprocessing. In addition, when, for example, chlorine is used as theetching gas, the amount of supplying the gas is preferably, for example,100 ml to 200 ml per minute. Similarly to the second mask 31 a, thefirst mask 21 a may remain at the time formation of the top pole tip 11a is completed, or may be eliminated in the etching process. Theabove-described approach enables formation of the top pole tip 11 a withhigh precision and in a short time. The above-described second bottompole 7 b can also be formed with high precision and in a short time byemploying the approach similar to that for the top pole tip 11 a informing the second pole 7 b.

[0092] The magnetic path connection portion 11 b is also formed by theapproach similar to that for the top pole tip 11 a. For forming themagnetic path connection portion 11 b, another mask 21 b (see FIG. 2A)is used which is formed of the same material and by the same step as thefirst mask 21 a.

[0093] The method of manufacturing a thin-film magnetic head accordingto the present embodiment will be further described with reference toFIG. 3B and FIG. 10.

[0094] As shown in FIG. 3B and FIG. 10, under the conditions similar tothose for forming, for example, the top pole tip 11 a, the write gaplayer 8 and the second bottom pole 7 b are etched with the RIE byapproximately 0.5 μm using as a mask the first mask 21 a (not shown inFIG. 3B) and the unillustrated photoresist film selectively disposed ona surface of a region M extending from the foremost position of thewidened width portion 11 a(2) of the top pole tip 11 a to the rearmostposition thereof, and on a surface of the magnetic path connectionportion 11 b (not shown in FIG. 10). At this time, the part of theinsulating film pattern 10 extending rearward from the rearmost end ofthe top pole tip 11 a is etched simultaneously. Through this etchingprocess, the write gap layer 8 and the second bottom pole 7 b areselectively removed to leave the portions corresponding to the tipportion 11 a(1) of the top pole tip 11 a, to thereby form a pole tip 100having a trim structure. The pole tip 100 is composed of the tip portion11 a(1) of the top pole tip 11 a, a portion (7 bF) of the second bottompole 7 b that corresponds to the tip portion 11 a(1), and part of thewrite gap layer 8 sandwiched therebetween, and each of these portionshas substantially the same width. The etching process with the RIEenables formation of the pole tip 100 with high precision and in a shorttime. In particular, when etching process is performed with the RIE toform the pole tip 100, etching gas containing chlorine of in the orderof 20 ml to 40 ml per minute and boron trichloride of in the order of 60ml to 80 ml per minute, for example, is preferably used.

[0095] No problems arise if the first mask 21 a is etched away duringthe above-described RIE process because, in such a case, the top poletip 11 a itself serves as an etching mask for the underlying regions(the write gap layer 8 and the second bottom pole 7 b). However, as thefilm thickness of the top pole tip 1 a is reduced by etching, the toppole tip 11 a is preferably formed thicker taking the reduced filmthickness into consideration. It should be noted that the tip portion 11a(1) corresponds to one specific example of a “first uniform widthportion” of the invention, and the portion 7 bF corresponds to onespecific example of a “second uniform width portion” of the invention.

[0096] As shown in FIG. 3A, an insulating layer 12 of 0.5 μm to 1.5 μmin thickness is formed of, for example, alumina over the entire surfaceof the layer structure as mentioned above.

[0097] Next, as shown in FIG. 3A, the thin-film coil 13 having athickness of approximately 1 μm to 2 μm used for an inductive-typerecording head formed of, for example, copper (Cu) is formed byelectrolytic plating on a region of the flat insulating film 12 locatedbetween the top pole tip 11 a and the magnetic path connection portion11 b. The thin-film coil 13 has, for example, a spiral planar structureas shown in FIG. 12, which will be described hereinafter. FIG. 3A showsonly part of the thin-film coil 13. At the same time the thin-film coil13 is formed, a coil connection portion 13 s is integrally formed withthe thin-film coil 13 at, for example, an inner end thereof located onthe insulating film 12. The coil connection portion 13 s is used forelectrically connecting the thin-film coil 13 and a coil connectionwiring 11 h (see FIG. 5A) which will be formed in a later step.

[0098] As shown in FIGS. 4A and 4B, an insulating film 14 of about 3 μmto 4 μm in thickness is formed of, for example, alumina over the entiresurface of the layer structure as mentioned above, to thereby burytherein an uneven configuration region composed of the top pole tip 11a, the magnetic path connection portion 11 b, the thin-film coil 13, thecoil connection portion 13 s, and the like. Thereafter, the entiresurface of the insulating film 14 is polished and planarized through,for example, the CMP. Here, the surface of the insulating film 14 ispolished until both the top pole tip 11 a and the magnetic pathconnection portion 11 b are exposed. Since each gap between turns of thethin-film coil 13 is filled with the insulating film 14, the turns areinsulated from each other. The materials which may be used for fillingin each gap between the turns of the thin-film coil 13 other thanalumina include, among others, insulating materials, such as photoresistor spin on glass (SOG), exhibiting fluidity when heated. Whenphotoresist, SOG, or the like is used for filling in the gaps betweenthe turns, these gaps are filled with such a material more tightly thanalumina, and therefore insulating effect can be more ensured. In such acase, it is preferable to first fill in the gaps between the turns withthe above insulating material, and then provide the insulating film 14formed of alumina thereon. By using alumina as a material for formingthe insulating film 14, a polishing surface of a CMP polishing disc canbe prevented from clogging, and the polished surface can be formed moresmoothly, different from the case of using a soft material, such asphotoresist.

[0099] As shown in FIGS. 5A and 5B, the portion of the insulating film14 covering over the coil connection portion 13 s is selectively removedthrough, for example, the RIE or ion milling, to thereby form an opening14 k for connecting the coil connection portion 13 s and the coilconnection wiring 11 h which will be formed in a later step.

[0100] As shown in FIGS. 5A and 5B and FIG. 11, the top yoke 11 c ofabout 2 μm to 3 μm in thickness, which will form part of the top pole11, is selectively formed on the portion of the planarized region thatextends from the magnetic path connection portion 11 b (not shown inFIG. 11) to the top pole tip 11 a. At the same time the top yoke 11 c isformed, the coil connection wiring 11 h (not shown in FIG. 11) is alsoformed at a region extending from the top portion of the opening 14 k toan external circuit (not shown). The coil connection wiring 11 h is usedfor electrically connecting the coil connection portion 13 s and theunillustrated external circuit. The top yoke 11 c and the coilconnection wiring 11 h are preferably formed of, for example, ironnitride, an amorphous alloy (zirconium-cobalt-iron), or the like, havinga high saturation magnetic flux density. Similarly to the top pole tip11 a and the magnetic path connection portion 11 b described above, thetop yoke 11 c and the coil connection wiring 11 h are formed by RIEunder a predetermined condition. The above-described method also makesit possible to form the top yoke 11 c and the coil connection wiring 11h with high precision and in a short time.

[0101] The top yoke 11 c has such a planar shape as, for example, shownin FIG. 12 described hereinafter, and includes a yoke portion 11 c(1)located over the thin-film coil 13 and a connection portion 11 c(2)partially overlapping the top pole tip 11 a and located in front of theyoke portion 11 c(1). In forming the top yoke 11 c, it is preferablethat the edge of its forefront portion (hereinafter referred to simplyas the “foremost end”) is located slightly in front of the foremost endof the insulating pattern 10, i.e. the throat height zero position (TH0position), and that the edge of its rearmost portion (hereinafterreferred to as the “rearmost end”) is substantially in line with therearmost end of the magnetic path connection portion 11 b. The top yoke11 c is magnetically coupled with the bottom pole 7 sandwiching themagnetic path connection portion 11 b in the opening 8 b, and is also incontact with, and therefore magnetically coupled with, the top pole tip11 a. It should be noted that the top yoke 11 c corresponds to onespecific example of a “second magnetic layer portion” of the invention,and the top pole 11 composed of the top pole tip 11 a, the magnetic pathconnection portion 11 b and the top yoke 11 c corresponds to onespecific example of a “first magnetic layer” of the invention.

[0102] As shown in FIGS. 5A and 5b, the overcoat layer 15 is formed of,for example, alumina covering the entire surface of the layer structureas mentioned above. Finally, the air bearing surface 20 of the recordingand reproducing heads is formed by machining or polishing, whereby athin-film magnetic head is completed.

[0103] Structure of Thin-Film Magnetic Head

[0104] A structure of the thin-film magnetic head of this embodimentwill next be described with reference to FIG. 12.

[0105]FIG. 12 schematically shows a planar structure of the thin-filmmagnetic head manufactured by the method of manufacturing a thin-filmmagnetic head according to the present embodiment. In FIG. 12, theinsulating films 12 and 14, the overcoat layer 15, and the like are notillustrated. In addition, the thin-film coil 13 is shown by only theoutermost periphery portion thereof in the figure, and the insulatingpattern 10 is shown by only the outermost end thereof in the figure.FIG. 5A shows a cross section taken along the line VA-VA in FIG. 12. Thenotations for X, Y, and Z axis directions shown in FIG. 12 are the sameas those in FIGS. 1A and 1B through FIG. 11.

[0106] As shown in FIG. 12, the foremost end of an insulation layerconstituted of the insulating pattern 10, the insulating film 12 and theinsulating film 14 is located at the reference position for determiningthe throat height (TH), that is, throat height zero position(hereinafter referred to simply as “TH0 position”). The throat height(TH) is defined as the distance between the position of the foremost endof the insulating pattern 10 (TH0 position) and the air bearing surface20. The “MRH0 position” in FIG. 12 indicates the position of therearmost end of the MR film 5, that is, the MR height zero position. TheMR height is the distance between the MR height zero position and theair bearing surface 20.

[0107] The top pole 11 is composed of the top pole tip 11 a, themagnetic path connection portion 11 b, and the top yoke 11 c, formedseparately. In other words, the top pole 11 is an assembly of theseparts.

[0108] The top yoke 11 c includes the yoke portion 11 c(1) having alarge area for containing magnetic flux generated in the thin-film coil13, and the connection portion 11 c(2) having a uniform width smallerthan the yoke portion 11 c(1). The yoke portion 11 c(1) has, forexample, that is uniform width in a rear region, and is graduallydecreased in a front region as it approaches the air bearing surface 20.The connection portion 11 c(2) has such a width, for example, that isgreater than the maximum width of the widened width portion 11 a(2) of atop pole tip 11 a described hereinafter. It should be noted, however,that such widths as described above are only the examples, and the widthof the former may be, for example, smaller than the width of the latter.

[0109] The top pole tip 11 a has such a planar shape, for example, thatits width increases as it gets farther from the air bearing surface 20,and includes the tip portion 11 a(1) and the widened width portion 11a(2) in the order named from the air bearing surface 20. The tip portion11 a(1) has a uniform width almost all over the area, and the widthdefines a recording track width in recording. The widened width portion11 a(2) has a front portion having a greater width than the tip portion11 a(1), and a rear portion having an even greater width than the frontportion. In other words, a step in the width direction is created in acoupling portion of the tip portion 11 a(l) and the front portion of thewidened width portion 11 a(2). Both corners of the both portions (frontand rear portions) of the widened width portion 11 a(2) on the airbearing surface 20 side are, for example, chamfered and tapered.

[0110] A step surface 11 d in the step of the top pole tip 11 a on theside of the widened width portion 11 a(2) is positioned, for example,between the MRH0 position and the TH0 position. A front end surface litof the top yoke 11 c is positioned, for example, between the stepsurface 11 d of the top pole tip 11 a and the TH0 position. The positionof the end surface 11 t of the top yoke 11 c is not limited to the aboveexample, and the end surface 11 t may be, for example, in line with theTH0 position, or may be located behind the TH0 position. The centers ofthe top yoke 11 c and the top pole tip 11 a in the width directioncoincide with each other.

[0111] As shown in FIG. 5A, FIG. 11 and FIG. 12, part of the frontportion of the top yoke 11 c partially overlaps the widened widthportion 11 a(2) of the top pole tip 11 a, and is magnetically coupledthereto. As shown in FIGS. 5A and 5B and FIG. 12, the top yoke 11 c isalso magnetically coupled to the bottom pole 7 sandwiching the magneticpath connection portion 11 b in the opening 8 b. Therefore, the top pole11 (the top pole 11 a, the magnetic path connection portion 11 b, andthe top yoke 11 c) and the bottom pole 7 (the first and second bottompoles 7 a and 7 b, respectively) are connected, thereby forming apropagation path for magnetic flux, that is, magnetic path.

[0112] As shown in FIG. 12, the thin-film coil 13 is a winding with aspiral planar shape, and at an inner end thereof the coil connectionportion 13 s is formed integrally with the thin-film coil 13. An end ofthe coil connection wiring 11 h is in contact with the coil connectionportion 13 s and electrically connected thereto. The other end of thecoil connection wiring 11 h and an outer end 13 x of the thin-film coil13 are connected to an unillustrated external circuit, which enables tosupply electricity to the thin-film coil 13.

[0113] As can be seen from FIGS. 5A and 5B, FIG. 10, and FIG. 12, thetip portion 11 a(1) and the front portion of the widened width portion11 a(2) of the top pole 11 a extend over the flat write gap layer 8,while the rear portion of the widened width portion 11 a(2) extends overthe slope of the insulating pattern 10.

[0114] Function of the Thin-film Magnetic Head

[0115] Next, functions of a thin-film magnetic head according to thepresent embodiment will be described with reference to FIG. 5A, FIG. 11and FIG. 12.

[0116] Basic operation of the thin-film magnetic head, namely, operationof writing and reproducing data to and from a recording medium, will bebriefly described here.

[0117] In the thin-film magnetic head of the present embodiment, whencurrent flows to the thin-film coil 13 through an unillustrated externalcircuit in data writing operation, magnetic flux is generated inresponse thereto. The thus generated magnetic flux propagates from theyoke portion 11 c(1) to the connection portion 11 c(2) in the top yoke11 c, and then propagates through the widened width portion 11 a(2) ofthe top pole tip 11 a magnetically coupled with the top yoke 11 c to thetip portion 11 a(1). Magnetic flux reaching the tip portion 11 a furtherpropagates to the very tip portion thereof on the air bearing surface 20side, and generates a signal magnetic field for recording in an externalregion located in the vicinity of the write gap layer 8. This signalmagnetic field partially magnetizes the magnetic recording medium, sothat information is recorded therein.

[0118] On the other hand, in reproduction, sense current is applied tothe MR film 5 of the reproduction head. Since the resistance of the MRfilm 5 varies with a reproduction signal magnetic field from themagnetic recording medium, the change in resistance is detected by achange in sense current, to thereby read out information recorded on themagnetic recording medium.

[0119] Function and Effect of the Method of Manufacturing Thin-FilmMagnetic Head

[0120] Characteristic functions and effects of the method ofmanufacturing a thin-film magnetic head according to the presentembodiment will be described with reference to FIG. 9 and FIG. 10.

[0121] According to the present embodiment, as shown in FIG. 9, the toppole tip precursor layer 111 a (not shown in FIG. 9; see FIG. 8) isselectively etched and patterned through the RIE with use of the firstmask 21 a, to thereby form the top pole tip 11 a. The processing speedof the RIE is generally higher than that of the ion milling. Inaddition, in the etching process with RIE, especially chlorine-type gasis selected, and the process temperature is adjusted to be in a range of50° C. to 250° C. The etching conditions are thus optimized so as toenhance chemical reactivity during the etching process. Therefore, thetop pole tip 11 a can be formed in an extremely short time as comparedwith the related art method with ion milling. Such functions and effectscan also be obtained in forming other magnetic layer portions (thesecond bottom pole 7 b, the magnetic path connection portion 11 b, andthe top yoke 11 c), the pole tip 100, and the like by using the methodsimilar to that for forming the top pole tip 11 a. By forming the poletip 100 through RIE as described above, process time can be reduced ascompared to the process in which the tip portion 11 a(1) and the portion7 bF are formed by ion milling and the write gap layer 8 is selectivelyremoved by RIE.

[0122] According to the present embodiment, iron nitride, an amorphousalloy (zirconium-cobalt-iron), or the like is used for forming the toppole tip precursor layer 111 a, and the top pole tip precursor layer 111a formed of such a material is etched through the RIE, whereby the toppole tip 11 a can be formed with high precision. Such functions andeffects can be obtained in forming other magnetic layer portions thanthe top pole tip 11 a by using the similar material and method. It isparticularly made possible to avoid a partial increase in width of theunetched portion caused by reattachment of etching products, which isthe case in the related art method where a plated film of permalloy issubjected to ion milling, or avoid a partial decrease in width of theunetched portion due to excessive etching, and the like. As a result,the pole tip 100 can be made uniform throughout the thickness directionand the height direction as shown in FIG. 10.

[0123] As described above, according to the method of manufacturing athin-film magnetic head of the present embodiment, the respectivemagnetic layer portions (the second bottom pole 7 b, the top pole tip 11a, the magnetic path connection portion 11 b, the top yoke 11 c, and thelike) constituting a thin-film magnetic head is formed through the RIEunder the appropriate conditions, to thereby reduce the time requiredfor such formation as compared to the related art method with ionmilling. Since the top pole tip 100 with a trim structure is also formedthrough the RIE, the time required for manufacturing the entirethin-film magnetic head can be significantly reduced.

[0124] According to the present embodiment, iron nitride, an amorphousalloy (zirconium-cobalt-iron), or the like is used for forming the abovemagnetic material layers, and therefore each magnetic layer portion canbe formed with high precision. The pole tip 100 including the tipportion 11 a(l) of the top pole tip 11 a has an uniform width over theentire region, whereby stable recording characteristics can be obtained,and the narrow magnetic pole for the sake of higher recording densitycan be achieved.

[0125] According to the present embodiment, an inorganic material, suchas alumina, with slower etching rate is used as a material of the firstmask 21 a for patterning the top pole tip precursor layer 111 a, theetched amount of the first mask 21 a itself can be reduced as comparedwith the case where a soft material with a high etching rate, such asphotoresist, is used as a material of the first mask 21 a. As a result,a loss in thickness of the top pole tip 11 a formed eventually can bereduced. Such effect can also be obtained for the magnetic pathconnection portion 11 b formed by another mask 21 b of alumina.

[0126] According to the present embodiment, the first mask 21 a is alsoformed through the RIE, so that the time required for forming the firstmask 21 a can be reduced as compared to the process with ion milling.This also contributes to reduction in time for manufacturing the entirethin-film magnetic head.

[0127] According to the present embodiment, an inorganic material with arelatively low reflectance, such as alumina, is used for forming thefirst mask precursor layer 121 a, and therefore deformation of thephotoresist film due to the adverse effect of reflected light duringexposure can be suppressed when the second mask precursor layer 131 a ispatterned through photolithography to form the second mask 31 a.Consequently, the second mask 31 a can be formed with high precision aswell as the first mask 21 a and the top pole tip 11 a.

[0128] According to the present embodiment, when the pole tip 100 isformed by etching with the RIE, a region (such as the second bottom pole7 b and the like) where the thin-film coil 13 will be formed in a laterstep is also etched, so that the surface of the region where thethin-film coil 13 is formed is positioned lower than the bottom surfaceof the top pole tip 11 a. Therefore, when the insulating film 14 ispolished by the CMP until both the top pole tip 11 a and the magneticpath connection portion 11 b are exposed after the thin-film coil 13 isburied with the insulating film 14, the insulating film 14 having asufficient thickness exists on the thin-film coil 13. As a result,insulation between the thin-film coil 13 and the top yoke 11 c whichwill be formed in a later step can be ensured.

[0129] According to the present embodiment, while iron nitride, anamorphous alloy (zirconium-cobalt-iron), or the like is used as amaterial of the magnetic material layer for forming the respectivemagnetic layer portions constituting the thin-film magnetic head, othermaterials, such as permalloy, may be used. However, when permalloy isused for forming the magnetic material layer, the ratio of nickel (Ni)in the composition is preferably, for example, 45% or less. By thusdecreasing the ratio of nickel in the composition, reattachment of theetching products can be prevented during the etching process with RIE.

[0130] While an electrolytic plating is employed for forming the bottomshield layer 3 and the first bottom pole 7 a in the present embodiment,the formation method is not limited thereto, and both, or either one, ofthese portions may be formed, for example, by sputtering. In such acase, iron nitride, as well as permalloy as in the above example, can beused as the material. By thus using the method similar to that for thetop pole tip 11 a and the like, each portion can be formed with highprecision and in a short time, which also contributes to reduction intime for forming the entire thin-film magnetic head.

[0131] While the bottom pole 7 has a two-layered structure in thepresent embodiment, the present invention is not limited thereto, andthe bottom pole 7 may be formed of, for example, a single layer. Whenthe bottom pole 7 has a single layer, the manufacturing process can besimplified as compared with the two-layered structure.

[0132] Although the tip portion 11 a(1) of the top pole tip 11 a and theportion 7 bF of the second bottom pole 7 b forming the pole tip 100 aresuccessively formed in the present embodiment, the above description isonly an example, and the portion 7 bF may be formed, for example,immediately after forming the second bottom pole 7 b.

[0133] While the write gap layer 8 is formed of alumina by sputtering inthis embodiment, the material and manufacturing method are not limitedto such examples. Other than alumina, the materials of the write gaplayer 8 may be, for example, an inorganic insulating material, such asaluminum nitride (AlN), silicon oxide, silicon nitride, or the like, ora non-magnetic metal, such as tantalum (Ta), tungsten-titanium (WTi),titanium nitride (TiN), or the like. Further, the write gap layer 8 maybe formed by a chemical vapor deposition (CVD), as well as bysputtering. If the write gap layer 8 is formed by such a method, it ispossible to suppress creation of a pin hall in the gap layer, to therebyavoid leakage of magnetic flux through the write gap layer 8. Such aneffect is advantageous especially when the write gap layer 8 is formedin a small thickness.

[0134] While the top yoke (11 c) is described as having a single layerstructure formed of iron nitride in the present embodiment, it is notlimited to such a structure, and, as shown in FIGS. 13A and 13B, the topyoke may, for example, have a structure (211 c) where a layer 41 formedof a material with high saturation magnetic flux density, such as ironnitride, and a layer 42 formed of an inorganic insulating material, suchas alumina, are stacked alternately. When the top yoke is provided withsuch a structure, eddy current can be prevented from generating in themagnetic path, to thereby improve high frequency characteristics. Whenthe above layer 41 formed of a material with high saturation magneticflux density and a layer 42 formed of an inorganic insulating materialare both formed through the RIE, the time required for the formation canbe reduced. The portions other than the top yoke 211 c shown in FIGS.13A and 13B are the same as those shown in FIGS. 5A and 5B describedabove.

[0135] While the second mask precursor layer 131 a is formed of aphotoresist film and selectively patterned through the photolithographyto form the second mask 31 a in the present embodiment, the presentinvention is not limited thereto. For example, the second mask may beformed of a predetermined metal film. An example of forming the secondmask of a metal film will be described with reference to FIG. 14 to FIG.17. In FIG. 14 to FIG. 17, the components same as those shown in FIG. 6are indicated by the same reference characters, and description thereofwill be omitted.

[0136] Variation 1-1

[0137]FIG. 14 and FIG. 15 are the views for describing a first variationof the present embodiment. In this variation, a second mask precursorlayer 151 a formed of, for example, iron nitride, is formed by, forexample, sputtering on the first mask precursor layer 121 a, as shown inFIG. 14. At a prescribed position on the second mask precursor layer 151a, a third mask 81 a formed of, for example, a photoresist film isprovided. Using the thus formed third mask 81 a as an etching mask, thesecond mask precursor layer 151 a is selectively etched by, for example,ion milling, to thereby form a second mask 51 a as shown in FIG. 15. Itshould be noted that the third mask 81 a has a shape corresponding tothe planar shape of the top pole tip 11 a. As the steps following thestep of forming the second mask 51 a are the same as those in theabove-described embodiment, description thereof will be omitted. Evenwhen the thus formed second mask 51 a is used, the same effects as thoseof the above-described embodiment can be obtained. The second maskprecursor layer 151 a may also be formed of a metal other than ironnitride (such as permalloy). In such a case, the second mask precursorlayer 151 a may be formed of a plated film obtained by growing permalloyor the like by electrolytic plating. It should be noted that the secondmask precursor layer 151 a corresponds to one specific example of a“metal layer” of the invention, and the second mask 51 a corresponds toone specific example of the “second mask” as the “metal film pattern” ofthe invention formed by selectively etching the metal layer.

[0138] Variation 1-2

[0139]FIG. 16 and FIG. 17 are the views for describing a secondvariation of the present embodiment. In this variation, an electrodefilm (not shown) used as a seed layer in electrolytic plating is formedof, for example, permalloy in a thickness of about 70 nm by, forexample, sputtering on the first mask precursor layer 121 a. On thiselectrode film, a photoresist film is formed in a thickness of, forexample, about 1 μm to 2 μm, and selectively patterned throughphotolithography, to thereby form a photoresist pattern 171 a having anopening 171 x in a prescribed shape, as shown in FIG. 16. The planarshape of the opening 171 x corresponds to that of the top pole tip 11 a.If the thickness of the photoresist film is as small as about 1 μm orsmaller, adverse effects of light reflected from the electrode film(seed layer) during exposure can be suppressed, contributing to highlyprecise formation of the opening 171 x. Next, a second mask 71 a isformed of a plated film by growing, for example, permalloy in theopening 171 x by electrolytic plating using the above electrode film asa seed layer as shown in FIG. 17. It should be noted that FIG. 17 showsthe state after the photoresist pattern 171 a is removed. As the stepsfollowing the step of forming the second mask 71 a are the same as thosein the above-described embodiment, description thereof will be omitted.Even when the subsequent steps are proceeded by using such a second mask71 a, the same effects as those of the above-described embodiment can beobtained. It should be noted that the second mask 71 a corresponds toone specific example of the “second mask” as the “metal film pattern” ofthe invention formed of a plated film.

[0140] Variation 1-3

[0141] While the pole tip 100 is formed only by the etching process withthe RIE as shown in FIG. 3B and FIG. 10 in the above embodiment, thepole may be formed by other methods. The smallest possible pole width islimited to about 0.3 μm if the above-described method is employed, andthe precision in processing the pole tip 100 will be significantlydeclined if the pole width is equal to or smaller than 0.3 μm. As amethod of achieving the pole width (pole 100P) of equal to or less than0.3 μm, etching with both RIE and focused ion beam (FIB) is effective,as shown in FIG. 18 to FIG. 20. FIG. 18 is an enlarged view of a planarshape of the pole 100P and surrounding regions in etching. FIG. 19 showsa cross-sectional structure of the pole 100P and the surrounding regionsafter the etching process. FIG. 20 is an enlarged perspective view ofthe pole 100P and the surrounding regions after the etching process.Each of these figures shows the step subsequent to the step shown inFIG. 9 in the above embodiment, and the components same as those in FIG.9 of the above embodiment are indicated by the same referencecharacters. In addition, description related to the X, Y, and Z axisdirections in these figures are the same as those in the aboveembodiment. FIG. 18 shows only part of the widened portion 11 a(2) andthe tip portion 11 a(l) of the top pole tip 11 a, and the rest of theportions are omitted therein. FIG. 19 is a cross sectional view takenalong the line XIX-XIX in FIG. 18.

[0142] In order to form the pole 100P by the etching process with bothRIE and FIB, the top pole tip 11 a (the width of the tip portion 11 a(l)is represented as W1, where W1 is greater than or equal to 0.3 μm) isfirst formed by the RIE. Next, as shown in FIG. 18, a region 500 shownin the figure, for example, is etched by the FIB, to thereby remove theportion of the tip portion 11 a(l) corresponding to the region 500.Subsequently, the portions of the write gap layer 8 and the secondbottom pole 7 b corresponding to the region 500 are removed, to therebyform the pole 100P having a trim structure. As shown in FIG. 19, thepole 100P formed by the above etching process has a width W2 smallerthan W1 (W2<0.3 μm), that is, the pole width can be further narrowed. Inaddition, this width is constant with high precision throughout thethickness direction and the length direction.

[0143] The portions of the write gap layer 8 and the second bottom pole7 b corresponding to the region 500 are partially dug deeply, andespecially in the second bottom pole 7 b, a groove 100M having, forexample, a V-shaped cross sectional structure is formed. When theetching process is performed with the FIB, a width W3 of the groove 100Mat the outermost surface of the second pole 7 b is preferably about 1 μmor greater. This is because the width W3 of the groove 100M equal to orgreater than about 1 μm can prevent generation of the side erase inrecording due to adverse effects of part (portion 7 bS) of the secondbottom pole 7 b. A three-dimensional structure at this time is shown inFIG. 20. As a result, the pole width is narrowed with high precision,and therefore recording characteristics with higher density andstability can be obtained. When the etching process with both RIE andFIB is employed, it is also possible to first form the pole tip 100 withthe pole width W1 through RIE and reduce the width to the pole width W2through FIB. The step of forming the insulating film 12 and thesubsequent steps are the same as those shown in FIGS. 3A and 3B and soon in the above-described embodiment.

[0144] Second Embodiment

[0145] A second embodiment of the present invention will next bedescribed.

[0146] A method of manufacturing a composite thin-film magnetic head asa method of manufacturing a thin-film magnetic head according to asecond embodiment of the invention will be described with reference toFIGS. 21A and 21B to FIGS. 25A and 25B. A thin-film magnetic headaccording to this embodiment will also be described because it isembodied by the method of manufacturing a thin-film magnetic head ofthis embodiment. Each of FIG. 21A to FIG. 25A illustrates a crosssection perpendicular to the air bearing surface, while each of FIG. 21Bto FIG. 25B illustrates a cross section in parallel to the air bearingsurface of the pole. The notations related to X, Y, and Z axisdirections in FIGS. 21A and 21B to FIGS. 25A and 25B are the same asthose in the above-described first embodiment, and the components inthese figures identical to those in the first embodiment are indicatedby the same reference characters.

[0147] In the method of manufacturing a thin-film magnetic head of thepresent embodiment, the steps up to the step of burying the MR film 5 inthe shield gap films 4 and 6 shown in FIGS. 21A and 21B are the same asthose shown in FIGS. 1A and 1B in the first embodiment, descriptionthereof will be omitted.

[0148] According to the present embodiment, after the MR film 5 isburied in the shield gap films 4 and 6, a bottom magnetic layer 7 cwhich will be part of the bottom pole 7 is selectively formed in athickness of about 1 μm to 2 μm in a front region located on the shieldgap film 6, as shown in FIGS. 21A and 21B. An insulating film 400 ofalumina is formed over the entire surface of the layer structure asmentioned above, the surface of the insulating film 400 is polished bythe CMP until the bottom magnetic layer 7 c is exposed, and then theentire surface is planarized.

[0149] At the same time a bottom pole tip 7 d of about 1.5 μm to 2.5 μmin thickness, which will be part of the bottom pole 7, is selectivelyformed in a front region located on the bottom magnetic layer 7 c, abottom connection portion 7 e having the similar thickness, which willalso be part of the bottom pole 7, is selectively formed in a rearregion located on the bottom magnetic layer 7 c.

[0150] The bottom magnetic layer 7 c, the bottom pole tip 7 d and thebottom connection portion 7 e above are formed in a manner similar tothe top pole tip 11 a in the first embodiment. More specifically, alayer of iron nitride deposited by sputtering, for example, is patternedthrough RIE using a mask of alumina. Such a formation method makes itpossible to form the above components constituting the bottom pole 7with high precision and in a short time. It should be noted that thebottom magnetic layer 7 c may also be formed by the electrolytic platingusing, for example, permalloy. In forming the bottom pole tip 7 d, it ispreferable that the rearmost end thereof is positioned behind therearmost end of the MR film 5 (MRH0 position) by about 1 μm to 3 μm. Informing the bottom connection portion 7 e, it is preferable that therearmost end thereof is in line with that of the bottom magnetic layer 7c. It should be noted that the bottom pole 7 composed of the bottommagnetic layer 7 c, the bottom pole tip 7 d, and the bottom connectionportion 7 e corresponds to one specific example of the “second magneticlayer” of the invention.

[0151] Next, as shown in FIGS. 21A and 21B, an insulating film 31 of,for example, alumina is formed over the entire surface of the layerstructure as mentioned above in a thickness of about 0.5 μm to 1.5 μm.

[0152] As shown in FIGS. 22A and 22B, a thin-film coil 32 for aninductive-type recording head is formed of, for example, copper (Cu) ina thickness of about 1 μm to 2 μm by, for example, electrolytic platingon a region of the insulating film 31 located between the bottom poletip 7 d and the bottom connection portion 7 e. The thin-film coil 32 hasthe structural features, for example, similar to those of the thin-filmcoil 13 in the above first embodiment. At the same time the thin-filmcoil 32 is formed, a coil connection portion 32 s is integrally formedwith the thin-film coil 32 at, for example, an inner end thereof locatedon the insulating film 31.

[0153] As shown in FIGS. 22A and 22B, an insulating film 33 of, forexample, alumina is formed in a thickness of about 3 μm to 4 μm over theentire surface of the layer structure as mentioned above, which is thenpolished by, for example, the CMP until the bottom pole tip 7 d and thebottom connection portion 7 e are exposed.

[0154] As shown in FIGS. 23A and 23B, the insulating film 33 is etchedby about 0.3 μm to 1.2 μm through, for example, RIE or ion milling, andsimultaneously part of a rear region of the bottom pole tip 7 d is alsoetched by a similar amount, to thereby form a concave portion 34. Atthis time, the thin-film coil 32 and the coil connection portion 32 smay be, or may not be, exposed at the surface of the concave portion 34.In forming the concave portion 34, a side wall of at least its frontedge portion is formed as a slope. On the concave portion 34, forexample, alumina is formed and patterned through, for example, ionmilling, to thereby selectively form an insulating film pattern 35 ofabout 0.5 μm to 2 μm in thickness. The insulating film pattern 35 has athickness greater than the depth of the concave portion 34, and thefront edge formed as a slope. As a result, the edge and the surroundingregion of the insulating film pattern 35 are tapered. The insulatingfilm pattern 35 defines the throat height zero position (TH0 position)and the apex angle (θ).

[0155] As shown in FIGS. 24A and 24B, a write gap layer 36 of about 0.15μm to 0.3 μm in thickness is formed of, for example, alumina over theentire surface of the layer structure as mentioned above. At this time,an opening 36 b is formed in the write gap layer 36 for connecting thebottom pole 7 and a top pole 61 to be formed in a later step. The writegap layer 36 corresponds to one specific example of the “gap layer” ofthe invention.

[0156] As shown in FIGS. 24A and 24B, the insulating layer 33, theinsulating film pattern 35, and the write gap layer 36 covering the coilconnection portion 32 s are partially etched through, for example, RIEor ion milling, to thereby form an opening 35 k for connecting the coilconnection portion 32 s and a coil connection wiring 61 h to be formedin a later step.

[0157] As shown in FIGS. 24A and 24B, the top pole 61 of about 1.5 μm to3 μm in thickness is selectively formed in a region extending from thearea located on the bottom connection portion 7 e over the positionwhere the air bearing surface 20 is formed in a later step. At the sametime the top pole 61 is formed, the coil connection wiring 61 h isselectively formed in a region extending from the area located on theopening 35 k to the rearward area. The top pole 61 and the coilconnection wiring 61 h are formed in a similar manner to the top poletip 11 a described in connection with the first embodiment. Morespecifically, after an iron nitride layer is formed over the entiresurface of the layer structure as mentioned above by sputtering, masks91 and 92 having a shape corresponding to the planar shapes of the toppole 61 and the coil connection wiring 61 h, respectively, are disposedat predetermined positions on the surface of the iron nitride layer, andthe iron nitride layer is patterned through RIE under a predeterminedcondition. Such a method enables formation of the top pole 61 and thecoil connection wiring 61 h with high precision and in a short time. Themasks 91 and 92 used for forming these regions may remain after suchformation, or may be removed by etching. The top pole 61 has a planarshape, for example, as shown in FIG. 26, which will be describedhereinafter, and has a tip portion 61 a defining a recording track widthon the recording medium, an intermediate portion 61 b having a widthgreater than the tip portion 61 a, and a yoke portion 61 c havinggreater width and area than the intermediate portion 61 b. Thestructural features of the top pole 61 will be described hereinafter indetail. The tip portion 61 a and the intermediate portion 61 bcorrespond to one specific example of the “first magnetic layer portion”of the invention, and the yoke portion 61 c corresponds to one specificexample of the “second magnetic layer portion” of the invention. The toppole 61 corresponds to one specific example of the “first magneticlayer” of the invention.

[0158] As shown in FIG. 25B, the write gap layer 36 and the bottom poletip 7 d are etched by approximately 0.5 μm through dry etching with RIE,similarly to the case where the top pole tip 100 is formed in the abovefirst embodiment, to thereby form a pole 150 having a trim structure.Such an etching process with RIE makes it possible to form the pole 150with higher precision and in a shorter time than other methods, such asion milling. This etching process is performed by using as a mask aphotoresist film (not shown) selectively formed in a region of the toppole 61 excluding the region corresponding to the tip portion 61 a. Thepole 150 is composed of the tip portion 61 a of the top pole 61, aportion (7 dF) of the bottom pole tip 7 d corresponding to the tipportion 61 a, and part of the write gap layer 36 sandwiched by the aboveportions, and these components have substantially the same width. Thetip portion 61 a corresponds to one specific example of the “firstuniform width portion” of the invention, and the portion 7 dFcorresponds to one specific example of the “second uniform widthportion” of the invention.

[0159] As shown in FIG. 25A, an overcoat layer 80 of, for example,alumina is formed over the entire surface of the layer structure asmentioned above, and the air bearing surface 20 is formed by machiningor polishing, whereby the thin-film magnetic head according to thepresent embodiment is completed.

[0160]FIG. 26 schematically shows a planar structure of the thin-filmmagnetic head formed by the method of manufacturing a thin-film magnetichead according to the present embodiment. In FIG. 26, the componentsidentical to those in FIG. 12 of the first embodiment are labeled withthe same reference characters. In FIG. 26, the insulating film 33, themasks 91 and 92, the overcoat layer 80, and the like are omitted. Thethin-film coil 32 is indicated only by its outer periphery portion, andthe insulating film pattern 35 is indicated only by its outermost end.FIG. 25A is a cross sectional view taken along the line XXVA-XXVA inFIG. 26.

[0161] As shown in FIG. 26, the foremost end of the insulating filmpattern 35, i.e. the throat height zero position (TH0 position) issubstantially in line with the rearmost end of the MR film 5, i.e. theMRH0 position. However, the positional relationship is not limited tothe above example, and the TH0 position may be, for example, behind theMRH0 position.

[0162] The top pole 61 includes the tip portion 61 a, the intermediateportion 61 b and the yoke portion 61 c, in the order approaching the airbearing surface 20, which are formed as an integral body. The tipportion 61 a is the portion defining a recording track width on therecording medium in recording. In other words, the width of the tipportion 61 a defines the track width. The intermediate portion 61 b hasa width greater than the tip portion 61 a, and the yoke portion 61 c hasa width greater than the intermediate portion 61 b. The yoke portion 61c has a structure substantially similar to that of the yoke portion 11c(l) of the top yoke 11 c in the first embodiment. At a portion wherethe tip portion 61 a and the intermediate portion 61 b are coupled, astep is created in the width direction. The position of a step surface61 d in the step on the side of the intermediate portion 61 b issubstantially in line with the TH0 position (or the MRH0 position).However, such position is only an example, and the step surface 61 d maybe in front of, or behind, the TH0 position (or the MRH0 position).

[0163] As shown in FIG. 25A and FIG. 26, part of the rear region of thetop pole 61 is magnetically coupled sandwiching the bottom connectionportion 7 e to the bottom magnetic layer 7 c and the bottom pole tip 7 din the opening 36 b. Therefore, the top pole 61 and the bottom pole 7(the bottom magnetic layer 7 c, the bottom pole tip 7 d, and the bottomconnection portion 7 e) are connected, to thereby form a magnetic path.

[0164] The structural features of the components shown in FIG. 26 otherthan those described above are the same as those of the first embodiment(FIG. 12).

[0165] According to the present embodiment, the respective components(the tip portion 61 a, the intermediate portion 61 b, and the yokeportion 61 c) of the top pole 61 are integrally formed, and thereforethe manufacturing process can be simplified as compared to the firstembodiment where the respective portions (the top pole tip 11 a and thetop yoke 11 c) of the top pole 11 are formed separately.

[0166] According to the present embodiment, the insulating film pattern35 of alumina for defining the throat height (TH) and the apex angle (θ)is formed to part of its lower portion be buried in the convex portion34. As a result, the apex angle (θ) can be reduced as compared to thecase where the insulating film pattern 35 is formed directly on thepolished and planarized surface without the convex portion 34 provided.As the edge and its surrounding region of the insulating film pattern 35are tapered, such a shape also contributes to reduction in the apexangle (θ), and to a smoother flow of magnetic flux over the taperedportion, especially.

[0167] Since the insulating film pattern 35 having a sufficientthickness is formed over the thin-film coil 32 in the presentembodiment, insulation between the thin-film coil 32 and the top pole 61can be ensured.

[0168] Functions, effects, and variations of the method of manufacturinga thin-film magnetic head of the present embodiment other than thosedescribed above are the same as those in the first embodiment, andtherefore description thereof will be omitted.

[0169] While the insulating film pattern 35 is formed of alumina in thisembodiment, the material is not limited thereto, and photoresist, orSOG, for example, may be used. If such a material is used, heattreatment is applied to the formed photoresist film or SOG film at atemperature of, for example, 200° C. to 250° C. to fluidize photoresistor SOG, so that the front edge portion of the film has a tapered shape.

[0170] Although polishing the surface of the insulating film 33 isstopped when the bottom pole tip 7 d and the connection portion 7 e areexposed in this embodiment, it is not limited thereto, and polishing maycontinue until the thin-film coil 32, as well as the above parts, areexposed. In such a case, it is preferable that the insulating pattern 35is formed on the polished and planarized surface without forming theconcave portion 34, so as to avoid loss in film thickness of thethin-film coil 32 caused by etching the thin-film coil 32 in forming theconcave portion 34.

[0171] While the pole 150 is formed through RIE in this embodiment, theformation method is not limited thereto, and both the RIE and FIB may beemployed as described in connection with the variations 1-3 of the firstembodiment.

[0172] While the present invention has been described in the context ofthe preferred embodiments thereof, the invention is not limited to theseembodiments but can be varied in numerous ways. For example, it isrecommended in the above description of the embodiments that therespective magnetic layer portions constituting the thin-film magnetichead are formed by selectively etching the iron nitride layer throughRIE in order to enhance formation precision and speed. However, such aformation method need not be employed to all the magnetic layerportions. For instance, part of the respective magnetic layer portionsmay be formed of permalloy or the like by electrolytic plating. Itshould be noted, however, that at least the portion requiring highprecision in formation, i.e. the portion constituting the pole (the toppole tip 11 a and the second bottom pole 7 b in the first embodiment,and the top pole 61 and the bottom pole tip 7 d in the secondembodiment) are preferably formed by selectively etching iron nitridethrough RIE.

[0173] Further, the planar shapes of the top pole tip 11 a and the topyoke 11 c are not limited to those shown in FIG. 12, and can be modifiedas desired as long as the requirement of fully supplying the magneticflux generated by the thin-film coil 13 to the very tip of the tipportion 11 a(1). Similarly, the planar shape of the top pole 61 may alsobe modified.

[0174] Further, while the method of manufacturing a composite thin-filmmagnetic head is described in connection with the above embodiments andvariations, the present invention may also be applied to a thin-filmmagnetic head for recording use only having an inductive-type magnetictransducer for writing, and to a thin-film magnetic head for bothrecording and reproduction having an inductive-type magnetic transducer.The present invention may also be applied to a thin-film magnetic headhaving a structure where the order of stacking the elements for writingand reading are reversed.

[0175] As described above, according to the method of manufacturing athin-film magnetic head of the invention, at least one of the step offorming the first magnetic layer and the step of forming the secondmagnetic layer includes the steps of forming a magnetic material layerand selectively etching the magnetic material layer by reactive ionetching. As a result, the time required for etching is reduced ascompared to the case where the magnetic material layer is processedthrough ion milling. Consequently, the time required for manufacturingthe entire thin-film magnetic head can be significantly reduced.

[0176] According to the method of manufacturing a thin-film magnetichead of one aspect of the invention, the first mask is formed of amaterial including aluminum oxide or aluminum nitride. As a result, aloss in thickness of the first magnetic layer portion can be reduced ascompared to the case where a material with a high etching rate, such asphotoresist film, is used for forming the first mask.

[0177] According to the method of manufacturing a thin-film magnetichead of another aspect of the invention, as the first mask is formed byreactive ion etching, the time required for forming the first mask canbe reduced.

[0178] According to the method of manufacturing a thin-film magnetichead of still another aspect of the invention, formation of the firstuniform width portion of the first magnetic layer, selective removal ofthe gap layer excluding the portion corresponding to the first uniformwidth portion, and formation of the second uniform width portion of thesecond magnetic layer are successively formed. As a result, the timerequired for manufacturing the entire thin-film magnetic head can bereduced.

[0179] According to the method of manufacturing a thin-film magnetichead of still another aspect of the invention, the third magnetic layeris formed by reactive ion etching. As a result, the third magnetic layercan be formed with high precision and in a short time, to therebyachieve further reduction in time for manufacturing the entire thin-filmmagnetic head.

[0180] According to the method of manufacturing a thin-film magnetichead of still another aspect of the invention, a material containingiron nitride, or a material containing zirconium-cobalt-iron (amorphousalloy) is used as a material of the magnetic material layer. As aresult, reattachment can be reduced in etching the magnetic materiallayer through RIE as compared to the case where permalloy or the like isused, to thereby achieve a high precision patterning.

[0181] According to the method of manufacturing a thin-film magnetichead of still another aspect of the invention, the processing step isperformed at a temperature in a range of 50° C. to 300° C., andtherefore the time required for etching can be reduced.

[0182] According to the method of manufacturing a thin-film magnetichead of still another aspect of the invention, after a first etchingstep with reactive ion etching, a second etching step with focused ionbeam etching is performed, to thereby achieve formation of the firstuniform width portion of the first magnetic layer, selective removal ofthe region of the gap layer excluding the portion corresponding to thefirst uniform width portion, and formation of the second uniform widthportion of the second magnetic layer. As a result, the width of theunetched portion (masked portion) can be made narrower with a higherprecision than the width achieved only by the reactive ion etchingprocess.

[0183] According to the method of manufacturing a thin-film magnetichead of still another aspect of the invention, the groove is formedhaving at least 1 μm in width, to thereby prevent generation of sideerase during recording.

[0184] Obviously many modifications and variations of the presentinvention are possible in the light of the above teachings. It istherefore to be understood that within the scope of the appended claimsthe invention may be practiced otherwise than as specifically described.

What is claimed is:
 1. A method of manufacturing a thin-film magnetichead, the head comprising: first and second magnetic layers eachincluding a magnetic pole and magnetically coupled to each other, themagnetic poles facing each other with a gap layer in between and beingto be faced with a recording medium; and a thin-film coil portiondisposed between the two magnetic layers with an insulating film inbetween; the first magnetic layer including a first magnetic layerportion having a first uniform width portion that defines a track width,and a second magnetic layer portion extending a region where thethin-film coil portion is disposed and magnetically coupled to the firstmagnetic layer portion, the second magnetic layer including a seconduniform width portion corresponding to the first uniform width portionof the first magnetic layer, at least one of the step of forming thefirst magnetic layer and the step of forming the second magnetic layercomprising the steps of: forming a magnetic material layer; andselectively etching the magnetic material layer by reactive ion etching.2. A method of manufacturing a thin-film magnetic head according toclaim 1 , wherein a first mask formed of a predetermined inorganicmaterial is used in the step of selective etching.
 3. A method ofmanufacturing a thin-film magnetic head according to claim 2 , wherein amaterial for forming the first mask contains aluminum oxide or aluminumnitride.
 4. A method of manufacturing a thin-film magnetic headaccording to claim 2 , wherein the step of forming the first maskincluding the steps of: forming a mask precursor layer made of theinorganic material on a surface of the magnetic material layer; forminga second mask on a surface of the mask precursor layer; and patterningthe mask precursor layer with use of the second mask.
 5. A method ofmanufacturing a thin-film magnetic head according to claim 4 , whereinthe first mask is formed by reactive ion etching.
 6. A method ofmanufacturing a thin-film magnetic head according to claim 4 , wherein aphotoresist film pattern having a predetermined shape is formed on thesurface of the mask precursor layer, and used as the second mask.
 7. Amethod of manufacturing a thin-film magnetic head according to claim 4 ,wherein a metal film pattern having a predetermined shape is formed onthe surface of the mask precursor layer, and used as the second mask. 8.A method of manufacturing a thin-film magnetic head according to claim 7, wherein the metal film pattern is formed by selectively plating on thesurface of the mask precursor layer.
 9. A method of manufacturing athin-film magnetic head according to claim 7 , wherein the metal filmpattern is formed by forming a metal layer on the surface of the maskprecursor layer and selectively etching the metal layer.
 10. A method ofmanufacturing a thin-film magnetic head according to claim 1 , whereinat least the first uniform width portion of the first magnetic layer isformed by the step of selective etching.
 11. A method of manufacturing athin-film magnetic head according to claims 1, wherein at least thesecond uniform width portion of the second magnetic layer is formed bythe step of selective etching.
 12. A method of manufacturing a thin-filmmagnetic head according to claim 10 , wherein a region of the gap layerexcluding a portion corresponding to the first uniform width portion ofthe first magnetic layer is selectively removed by reactive ion etching.13. A method of manufacturing a thin-film magnetic head according toclaim 1 , wherein formation of the first uniform width portion of thefirst magnetic layer, selective removal of a region of the gap layerexcluding a portion corresponding to the first uniform width portion,and formation of the second uniform width portion of the second magneticlayer are achieved successively.
 14. A method of manufacturing athin-film magnetic head according to claim 13 , wherein the firstuniform width portion of the first magnetic layer is formed by using thefirst mask made of an inorganic material, and the selective removal ofthe gap layer and the formation of the second uniform width portion ofthe second magnetic layer are achieved by using as a mask at least oneof the first mask and the first uniform width portion.
 15. A method ofmanufacturing a thin-film magnetic head according to claim 1 , whereinin the step of forming the first magnetic layer, the second magneticlayer portion is formed separately from the first magnetic layer portionby reactive ion etching.
 16. A method of manufacturing a thin-filmmagnetic head according to claim 1 , the thin-film magnetic head furthercomprising a magnetic transducer film extending in a direction away froma recording-medium-facing surface to be faced with the recording medium,and a third magnetic layer magnetically shielding the magnetictransducer film, wherein the third magnetic layer is formed by reactiveion etching.
 17. A method of manufacturing a thin-film magnetic headaccording to claim 1 , wherein the magnetic material layer is formed bysputtering using a predetermined magnetic material.
 18. A method ofmanufacturing a thin-film magnetic head according to claim 17 , whereinthe magnetic material contains iron nitride.
 19. A method ofmanufacturing a thin-film magnetic head according to claim 17 , whereinthe magnetic material contains amorphous alloy.
 20. A method ofmanufacturing a thin-film magnetic head according to claim 19 , whereinamorphous alloy contains zirconium-cobalt-iron.
 21. A method ofmanufacturing a thin-film magnetic head according to claim 1 , whereinthe step of selective etching is performed in a gas atmospherecontaining at least one of chlorine, boron dichloride, borontrichloride, and hydrogen chloride.
 22. A method of manufacturing athin-film magnetic head according to claim 1 , wherein the step ofselective etching is performed at a temperature in a range of 50° C. to300° C.
 23. A method of manufacturing a thin-film magnetic head, thehead comprising: first and second magnetic layers each including amagnetic pole and magnetically coupled to each other, the magnetic polesfacing each other with a gap layer in between and being to be faced witha recording medium; and a thin-film coil portion disposed between thetwo magnetic layers with an insulating film in between; the firstmagnetic layer including a first magnetic layer portion having a firstuniform width portion that defines a track width, and a second magneticlayer portion extending a region where the thin-film coil portion isdisposed and magnetically coupled to the first magnetic layer portion,the second magnetic layer including a second uniform width portioncorresponding to the first uniform width portion of the first magneticlayer, the method comprising: a first etching step of selectivelyetching at least one of the first magnetic layer, the gap layer, and thesecond magnetic layer by reactive ion etching; and a second etching stepof selectively etching at least one of he first magnetic layer, the gaplayer, and the second magnetic layer by focused ion beam etching;wherein the second etching step is performed after the first etchingstep, to thereby achieve formation of the first uniform width portion ofthe first magnetic layer, selective removal of a region of the gap layerexcluding a portion corresponding to the first uniform width portion,and formation of the second uniform width portion of the second magneticlayer.
 24. A method of manufacturing a thin-film magnetic head accordingto claim 23 , wherein in the second etching step, both the gap layer andthe second magnetic layer are partially etched to form two grooveportions in the second magnetic layer so that a region sandwiched by thetwo groove portions serves as the second uniform width portion of thesecond magnetic layer.
 25. A method of manufacturing a thin-filmmagnetic head according to claim 24 , wherein the groove portion isformed to have a width of at least 1 μm.